/*
 * Copyright 2013-2018 Lilinfeng.
 *  
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *  
 *      http://www.apache.org/licenses/LICENSE-2.0
 *  
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package Nova.modbus.server;

import Nova.modbus.ModbusConstants;
import Nova.modbus.NettyConstant;
import Nova.modbus.codec.NettyMessageDecoder;
import Nova.modbus.codec.NettyMessageEncoder;
import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.codec.LengthFieldBasedFrameDecoder;
import io.netty.handler.logging.LogLevel;
import io.netty.handler.logging.LoggingHandler;
import io.netty.handler.timeout.ReadTimeoutHandler;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import java.io.IOException;

/**
 * @author Steven
 * @date 2020年10月24日
 * @version 1.0
 */

//  https://github.com/klymenek/modjn
public class NettyServer {

	private static final Log LOG = LogFactory.getLog(NettyServer.class);
	/*
	 * Modbus TCP Frame Description
	 *  - max. 260 Byte (ADU = 7 Byte MBAP + 253 Byte PDU)
	 *  - Length field includes Unit Identifier + PDU
	 *
	 * <----------------------------------------------- ADU -------------------------------------------------------->
	 * <---------------------------- MBAP -----------------------------------------><------------- PDU ------------->
	 * +------------------------+---------------------+----------+-----------------++---------------+---------------+
	 * | Transaction Identifier | Protocol Identifier | Length   | Unit Identifier || Function Code | Data          |
	 * | (2 Byte)               | (2 Byte)            | (2 Byte) | (1 Byte)        || (1 Byte)      | (1 - 252 Byte |
	 * +------------------------+---------------------+----------+-----------------++---------------+---------------+
	 */
    public void bind() throws Exception {
	// 配置服务端的NIO线程组
	EventLoopGroup bossGroup = new NioEventLoopGroup();
	EventLoopGroup workerGroup = new NioEventLoopGroup();
	ServerBootstrap b = new ServerBootstrap();
	b.group(bossGroup, workerGroup).channel(NioServerSocketChannel.class)
		.option(ChannelOption.SO_BACKLOG, 100)
		.handler(new LoggingHandler(LogLevel.INFO))
		.childHandler(new ChannelInitializer<SocketChannel>() {
		    @Override
		    public void initChannel(SocketChannel ch)
			    throws IOException {
			ch.pipeline().addLast("framer", new LengthFieldBasedFrameDecoder(ModbusConstants.ADU_MAX_LENGTH, 4, 2));
			ch.pipeline().addLast(
				new NettyMessageDecoder(1024 * 1024, 4, 4));
			ch.pipeline().addLast(new NettyMessageEncoder());
			ch.pipeline().addLast("readTimeoutHandler",
				new ReadTimeoutHandler(50000));
			ch.pipeline().addLast(new LoginAuthRespHandler());
			ch.pipeline().addLast("HeartBeatHandler",
				new HeartBeatRespHandler());
		    }
		});

	// 绑定端口，同步等待成功
	b.bind(NettyConstant.REMOTEIP, NettyConstant.PORT).sync();
	LOG.info("Netty server start ok : "
		+ (NettyConstant.REMOTEIP + " : " + NettyConstant.PORT));
    }

    public static void main(String[] args) throws Exception {
	new NettyServer().bind();
    }
}
